The invention relates to an electric power conversion system.
Inverters are a type off electric power conversion systems that have been in widespread use as speed controllers of motors in both industrial apparatuses and household appliance products. However, power semiconductors for use in power conversion, such as IGBTs used in such electric power conversion systems, generate heat due to electrical energy loss at the time of power conversion, and the power semiconductors therefore normally have a predetermined operating temperature limit. If power semiconductors continue to generate heat after their temperature exceeds the operating temperature limit, the risk arises that the power semiconductors may stop operation. Therefore, in such a case, there is a need for the electric power conversion system to include a structure for cooling the power semiconductors. More specifically, an air cooling method is facilitated by an electric power conversion system that is provided with cooling fins, and a cooling fan, so that heat from the power semiconductors, acting as heating elements, is conducted to the cooling fins, and air is sent out to the cooling fins by the cooling fan to cause heat exchange to take place.
In the paragraph (0019) of JP-A No. 9 (1997)-237992, a description is given of a masking shield 7 that serves as a shielding member between a main circuit 4, and a logical block 5 to thereby prevent air from either side to flow in, to eliminate a gap therebetween as much as possible, and to enable the masking shield 7 to have both a thermal insulation and magnetic shielding effect. The main circuit side of a system is respectively made up of an insulation material 9 while the logical block of the system is made up of a steel sheet 8 or the like. Furthermore, an air duct serving as a coolant path is provided therebetween, and the thermal insulation effect is furthered by causing air to flow through this air duct. In this configuration, the main circuit 4, and the logical block 5 are provided in chambers independent from each other.